JP2000162029A - Apparatus for measuring load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb the deformation enough in the horizontal direction and a tilting direction, with allowing a large vertical load, and enable the use in a place using solvents. SOLUTION: The load measuring apparatus comprises a measuring body 1 utilizing a strain gage, a load button 3 for transmitting the load to a pressure receiving plane 2 of the body 1, and a top plate 4 on one side of which the load button 3 is mounted and the other side of which an object to be measured loads. An elastic member 11 is sandwiched between the pressure receiving plane 2 and the top plate 4 around the load button 3 and the elastic member 11 is formed of a thin metal sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load measuring device using a strain gauge used for a platform scale, a material supply hopper, a compression / tensile testing machine, and the like.

[0002]

2. Description of the Related Art FIGS. 18 and 19 are a plan view and a front view showing an example of a conventional load measuring device 100. FIG. FIG.
As shown in FIG. 2, in the load measuring device 100, an elastic layer 106 made of rubber or a rubber-like elastic body is vulcanized and bonded between upper and lower face plates 104a and 104b. The elastic layer 106 is formed in a disk shape, and is considered so as to obtain mechanical characteristics (eg, compression stiffness and bending stiffness) substantially point-symmetric in each direction with respect to the center of the disk. Also, a lower surface plate 104b having substantially the same disk shape as the elastic layer 106
Is inserted into a cylindrical hole 102a provided in the center of the pressure receiving portion 102. The bottom surface of the pressure receiving portion 102 is positioned so as to rise from the installation surface, and the pressure receiving portion 102 and the frame-shaped fixing portion 10
1, a plurality of beam members 103 arranged around the pressure receiving portion 102 are fixed.
The strain gauges 107 are fixed to the upper and lower surfaces of the substrate 03 by bonding or the like. Therefore, the vertical load transmitted from the upper surface plate 104a pushes down the pressure receiving portion 102 via the elastic layer 106 and the lower surface plate 104b to bend the beam member 103, thereby changing the resistance value of the strain gauge 107. When a large load receiving surface is required by these load measuring devices, the load measuring devices 100 are arranged and used at the four corners of the load receiving plate 108 as shown in FIG. With these configurations, an elastic layer 106 is interposed between the upper surface plate 104a and the pressure receiving portion 102, and the upper surface plate 104a and the pressure receiving portion 102 can be relatively displaced in the horizontal direction and the tilting direction. Move the target object to the upper surface plate 104a or the load receiving plate 1
08 load measuring device 10
The load measuring device is protected by absorbing the external force applied to zero, the thermal shrinkage of each part, the formation error of the mounting hole, and the like.

[0003]

However, in the above-described conventional load measuring device, when a large vertical load is applied, the elastic layer 10 must have sufficient rubber hardness.
6 is compressed to the area beyond the capacity as an elastic body,
Sufficient deformation absorption by the elastic layer 106 cannot be obtained.
Therefore, in order to resist a large vertical load, the elastic layer 10 is required.
6, it is necessary to increase the rubber hardness, and as a result, the spring constant with respect to the displacement in the horizontal direction and the tilt direction becomes large, and there is a possibility that sufficient deformation absorption may not be obtained. Further, when rubber is used, there is also a problem that it cannot be used in a place where a solvent is used.

The object of the present invention has been made as a result of studying to solve such problems of the prior art, and it has been made possible to allow a large vertical load and provide sufficient horizontal and tilt directions. An object of the present invention is to provide a load measuring device which enables deformation absorption and also enables use in a place where a solvent is used.

[0005]

In order to achieve the above-mentioned object, the present invention provides a measuring instrument body using a strain gauge, a load button for transmitting a load to a pressure receiving surface of the measuring instrument body,
In a load measuring device having a top plate on which the load button is attached on one side and a load of an object to be measured on the other side, an elastic body is provided so as to be sandwiched between the pressure receiving surface and the top plate around the load button. And this elastic body is formed from a sheet metal material.

[0006]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0007] The embodiment shown in FIG.
A load button 3 formed of a hard material such as stainless steel that transmits a load to the pressure receiving surface 2 of the measuring device main body 1; and the load button 3 has one surface. And a top plate 4 which is mounted on one side and on which the load of the object to be measured is applied on the other side. Measuring instrument body 1
Is mounted on a base plate 5 made of a hard material such as stainless steel. The measuring device main body 1 includes a central portion 6 on which the pressure receiving surface 2 is formed, an installation portion 7 fixed to the base plate 5, and a strain generating portion 8 connecting the installation portion 7 and the central portion 6. A strain gauge 20 described later is attached to the strain-generating portion 8. Further, a cable 9 is connected to the measuring instrument body 1 to take out an output from the strain gauge 20 to the outside. The top plate 4 is connected to the pressure receiving surface 2 by a connecting member 10. Further, an elastic body 11 made of a thin metal plate material, in this example, stainless steel, is provided around the load button 3 so as to be sandwiched between the pressure receiving surface 2 and the top plate 4. The distal end of the connecting member 10 is fixed to the central portion 6. The connecting member 10 in this embodiment includes a head portion 10A and a shaft portion 10B that is thinner than the head portion 10A, and the tip of the shaft portion 10B is screwed from the pressure receiving surface 2 to the central portion 6. In addition, a large hole 12 and a small hole 13 are formed so as to communicate with each other on the top plate 4 where the connecting member 10 is provided. Small hole 1
The diameter of 3 is larger than the diameter of the shaft 10B, and the diameter of the large hole 12 is larger than the diameter of the head 10A. The diameter of the head 10A is larger than the diameter of the small hole 13. Due to such a relationship, the top plate 4 moves within a predetermined range in the horizontal direction, and can tilt about the load button 3. The installation part 7 of the measuring instrument body 1 is
5 is fixed to the base plate 5. A metal seal 16 is provided inside the installation portion 7 which is a donut-shaped frame and on the base plate 5, and a cap 17 is fitted into a hole opened in the center of the base plate 5. By providing the metal seal 16, the inside of the measuring instrument main body 1 is kept airtight, and dust and moisture are prevented from entering. The cap 17 is detached so that various adjustment resistors and the like inside can be operated.

FIG. 2 is a plan view in which the top plate 4, the load button 3, and the elastic body 11 in the left half of the drawing are omitted, and the measuring device main body 1 is formed in a disk shape. The omitted member in the left half is indicated by a two-dot chain line in the drawing.

FIG. 3 is a plan view of the top plate 4 alone. A large hole 12 and a small hole 13 for mounting the connecting member 10 are formed around the hole 4A where the load button 3 is mounted. The holes 4B at the four corners are for mounting members (members corresponding to the load receiving plates 108 in the conventional example) on the side of the object to be measured. FIG. 4 shows a cross section taken along the line AA of FIG. 3, and in this embodiment, it is made of stainless steel, has a thickness of 10 mm, and has a length and width of 12 mm.
5mm square plate-like material, the diameter of the large hole 12 is 17m
m, depth 8 mm, diameter of small hole 13 9 mm, depth 2
mm. The diameter of the hole 4A is 6 mm, and the diameter of the hole 4B is
Is 10 mm in diameter.

FIG. 5 is a simplified plan view of the measuring instrument main body 1 of the embodiment shown in FIG. 1, in which a strain gauge 20 is attached to the lower surface at a position where the circular strain generating portion 8 is divided into four equal parts. FIG. 6 shows a central longitudinal section of FIG. The lower surface of the central portion 6 is located at a position higher than the lower surface of the installation portion 7, and is supported in a floating state by a strain generating portion 8 extending inward from the installation portion 7. When a load is applied to the pressure receiving surface 2 which is the upper surface of the central portion 6, the strain generating portion 8 bends and the resistance value of the strain gauge 20 changes. The resistance value is detected and the magnitude of the load is measured. ing. The load applied to the top plate 4 is transmitted to the pressure receiving surface 2 via the load button 3. The lower surface of the load button 3 is formed as a spherical surface.

Another embodiment shown in FIG. 7 shows an example in which the height of the elastic body 11 is formed higher than the height of the load button 3 when the top plate 4 is unloaded. In a state where the load button 3 is not engaged, the lower surface of the load button 3 is in a state of floating from the pressure receiving surface 2.
There is a gap in the large hole 12 below the head 10A of the connecting member 10, and the top plate 4 can be moved up and down and tilted within the range of this gap. Also, there is a gap between the large hole 12 and the head 10A in the horizontal direction, and also a gap between the small hole 13 and the shaft portion 10B in the horizontal direction. Movement is allowed. The surface of the load button 3 facing the pressure receiving surface 2, that is, the lower surface is formed in a spherical surface, and the contact with the pressure receiving surface 2 is a point contact.

FIG. 8 shows a state in which the top plate 4 is tilted in the direction of the arrow, that is, a state in which the center axis of the load button 3 is tilted rightward in the drawing from a vertical state. Half is compressed. At this time, the head 10A of the connecting member 10 collides with the bottom of the large hole 12.

FIG. 9 shows a state in which a force in a direction indicated by an arrow, that is, a horizontal direction acts on the top plate 4.

The embodiment shown in FIG. 10 shows a state in which the tank 21 and the hopper mounting bracket 22 are mounted on the top plate 4. Bracket 2 for mounting this tank 21
2. Top plate 4 of measuring instrument body 1 at a plurality of locations
Install.

FIGS. 11 and 12 show a measuring instrument main body 1 having another shape. In this embodiment, an example in which the strain gauge 20 is formed in a rectangular shape instead of a disk shape is shown, and an example in which the strain gauges 20 are attached to both side surfaces of the strain generating portion 8 instead of the lower surface.

In the example of the measuring instrument main body 1 having still another shape shown in FIGS. 13 and 14, the whole is formed in a square shape, and the strain-generating portions 8 are provided on each side (one on each of four sides) of the central portion 6. An example in which the strain gauges are provided is shown, and a strain gauge 20 is attached to the lower surface of each of the strain generating portions 8.

FIG. 15 shows a central longitudinal section of the elastic body 11,
This shows an example in which a wavy portion 11A protruding inward is formed on the entire periphery of the center of the ring-shaped elastic body 11. This corrugated portion 11A can be protruded outward as shown in FIG. 1, or a plurality of corrugated portions 11A can be formed and formed into a bellows shape.

FIG. 16 shows still another example of the elastic body 11, wherein upper and lower flange portions 11B are formed, and these flange portions 11B are fixed to the top plate 4 and the central portion 6. As the fixing means, welding, bolting, or the like can be adopted.

The elastic body 11 as shown in FIGS.
Means that the wavy portion 11A is crushed by a vertical load and rotated (tilted)
When this occurs, the crushed portion follows the gap, so that no gap is formed between the top plate 4 and the pressure receiving surface 2. By preventing such a gap from being formed, dust, water, and the like do not enter between the top plate 4 and the elastic body 11.

In the embodiment shown in FIG. 17, the upper and lower ends of the elastic body 11 are provided with the grooves 41 and 6 provided in the top plate 4 and the central portion 6 respectively.
1 shows an example in which the elastic body 11 is fixed by being fitted into the elastic member 11.

In any of the above-described embodiments, the tilt direction,
There is a degree of freedom until the connecting member 10 contacts the walls of the large hole 12 and the small hole 13 in the horizontal direction and the vertical direction.
For example, a horizontal force generated by thermal contraction due to a temperature change of the tank 21 and a tilting power (rotational force) generated by bending of the mounting bracket 22 can be avoided. After being removed, it can be restored to the original position by the elastic restoring force of the elastic body 11. In addition, the displacement of the top plate 4 is prevented within a predetermined range, that is, the displacement is restrained by the contact of the connecting member 10 in the hole, and the connecting member 10 functions as a stopper. There is no need to provide a steady rest or a stopper on the surface. Furthermore, since the force in the vertical downward direction is transmitted to the measuring instrument body 1 by the load button 3, the elastic body 11 does not need to consider this force. Therefore, since the elastic body 11 only needs to have elasticity suitable for tilting power and horizontal force only, it is possible to have a compact shape with a small horizontal cross section.

[0022]

As described above, according to the present invention, an elastic body is provided around the load button so as to be sandwiched between the pressure receiving surface and the top plate, and this elastic body is formed from a thin metal plate. It is possible to sufficiently absorb deformation in the horizontal and tilt directions while allowing a large vertical load. Since the elastic body is made of a thin metal sheet, it is not deteriorated by organic solvents, chemicals, oils, etc. as in the case of rubber, and can be used even in an atmosphere where gases such as organic solvents exist. it can.

[Brief description of the drawings]

1 shows a preferred embodiment of the present invention; FIG.
FIG. 3 is a sectional view taken along line BCD.

FIG. 2 is a plan view in which one side of a top plate is omitted.

FIG. 3 is a plan view of a top plate.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a plan view of a measuring instrument main body.

FIG. 6 is a central longitudinal sectional view of FIG. 5;

FIG. 7 is a sectional view showing another embodiment.

FIG. 8 is a sectional view showing a state in which the top plate is tilted in the direction of the arrow.

FIG. 9 is a cross-sectional view showing a state in which the top plate has moved in the horizontal direction.

FIG. 10 is a front view of a state where the tank is mounted on a top plate.

FIG. 11 is a plan view showing another example of the measuring instrument main body.

FIG. 12 is a front view of FIG. 11;

FIG. 13 is a plan view showing still another example of the measuring instrument main body.

FIG. 14 is a front view of FIG. 13;

FIG. 15 is a central longitudinal sectional view of an elastic body.

FIG. 16 is a central longitudinal sectional view showing still another example of the elastic body.

FIG. 17 is a cross-sectional view illustrating an example of a method of fixing an elastic body.

FIG. 18 is a plan view showing a conventional example.

FIG. 19 is a front view of a conventional example.

FIG. 20 is a plan view showing an example in which a conventional measuring device is attached to four corners of a load receiving plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring instrument main body 2 Pressure receiving surface 3 Load button 4 Top plate 11 Elastic body 20 Strain gauge

Claims (1)

[Claims] 1. A measuring instrument main body using a strain gauge, a load button for transmitting a load to a pressure receiving surface of the measuring instrument main body, and the load button is mounted on one side and a load of an object to be measured is applied to the other side. In a load measuring device having a top plate, an elastic body is provided around the load button so as to be sandwiched between the pressure receiving surface and the top plate, and the elastic body is formed from a thin metal plate. apparatus.